CONTACTLESS DATA/POWER BUS

Abstract: An information display system for a store in which items placed on one or more shelves are selected therefrom, and wherein information relating to the items is shown on electronic display screens incorporated in display units mounted along the edge of the shelf, comprises a central data transmission source providing addressed data messages to a data distribution network, and the data distribution network including at least one conductive strip extending along the edge of a shelf and insulated therefrom, and a number of display units each having a capacitor plate positioned in close non-contact relation to the conductive strip. There is also described a method of converting a conventional shelf edge display apparatus, wherein a carrier strip holds a number of tickets of flexible sheet material along a shelf edge so as to expose one face of the tickets, to accept electronic information display units.

Description: New installations would also benefit from this device since it clearly allows a mixture of traditional paper labelling and electronic labelling. The adapter now provides a communication path with the electronic labels using capacitive or inductive coupling, or by radio frequency. An example of a system according to the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a shelf with a ribbon-like conductor along its edge and display devices associated therewith; and Figure 2 is a perspective view of a conventional carrier strip capable of accepting a paper label and/or a ribbon-like conductor strip. In the embodiment shown in the Figures, the ribbon 1 includes two parallel flat conductors that act as capacitor plates 2, the other halves of the capacitors being formed by suitably sized plates 3 provided in an electronic display unit 4, as seen in Figure 1. These plates 2, 3 are arranged to form the electrical circuit shown. By suitable electrical stimulation of the shelf edge plates 2, power and/or data may be transferred to the display unit plates 3, provided they are in close proximity. Clearly the form of the stimulation may be modulated in terms of frequency, amplitude or phase to carry said data. The shelf edge capacitor plates 2 are preferably formed by a film of a conductive material applied to a thin substrate of an insulating material. Suitable insulating materials include synthetic plastics materials, as well as the traditional paper-like materials. An effective and low cost means of applying the conductive element forming the plates or plates 2 is to use printing techniques with conductive ink. A conventional paper shelf edge label, on which price information can be written or printed, is about 30mm by 70mm. Such a label could be replaced by a ribbon conductor approximately 30mm wide extending along the shelf edge in the carrier originally installed to carry the conventional labels. The ribbon conductor is wide enough to support two plates 2 of 12mm width, spaced by 2mm from each other and from the edges of the ribbon. By providing capacitor plates 3 on the display unit which are 12mm wide and 70mm long, and using an air gap of 1.5mm between the plates 2 and 3, then a capacitance of about 20 pF would exist across the plates. There are thus two capacitors effectively in series in the circuit giving a usable capacitance of lOpF. If the stimulation frequency were set at 32 kHz then the capacitive reactance would be about 0.5 HOhm allowing at least 6 uAmps to flow given a 3 Volts r s amplitude input. This approximate calculation shows that it is possible to also pass power to a display device provided that it incorporates low power electronics, CMOS and LCD technology for example. Since the capacitive coupling is loose, the quantity of power that can be transferred is limited so that if the display device requires a lot of energy it must be self powered and the primary function of the plates 2 and 3 is to serve as a data channel only. A beneficial arrangement of a complete system would be to have the display units designed as slave devices to a master device that manages the whole shelf edge. The master device would be responsible for handling communications with the main system controller and could employ any of the extant techniques for this purpose. Information would be relayed to the slave units by use of the contactless bus. The bus could also provide a path for the slave devices to suitably acknowledge the reciept of messages back to the master. In essence a two way communications channel from slave to master will be effected. There are numerous existing designs of paper-carrying shelf edge label carriers, and thus the ribbon conductor would have to be designed to suit in each particular case. In the instance where the carrier is an integral part of the shelving metal work, the ribbon conductor could be applied in a self-adhesive form. This technique would also be employed where there is no special adaptation of the shelf edge to take a paper label and where the labels are placed into individual plastic mouldings that simply clip to the shelf facing edge.

Claims: CLAIMS 1. A data distribution network comprising a number of information display units supplied with data via a common data link, wherein the data link conprises a conductive element extending adjacent to the respective information display units, and a respective capacitance plate electrically connected to each respective information display unit and positioned in non-contact electrical connection with the conductive element. 2. A data distribution network according to claim 1, wherein the conductive element is a strip of electrically conductive material extending longitudinally along an elongate insulating substrate. 3. A data distribution network according to claim 2, wherein the substrate supports two or more conductive elements in a parallel array. 4. An information display system for a store in which items are placed on one or more shelves to be selected therefrom, and wherein information relating to the items is shown on electronic display screens incorporated in display units mounted along the edge of the respective shelf, the system comprising a central data transmission source providing addressed data messages to a data distribution network, and the data distribution network including at least one conductive strip extending along the edge of a shelf and insulated therefrom, and a number of display units each having a capacitor plate positioned in close non-contact relation to the conductive strip. 5. An information display system according to claim 4, wherein a pair of parallel conductive strips extend along the shelf edge, and wherein each display unit has a corresponding pair of capacitor plates each positioned in close non-contact relation to a respective one of the conductive strips. 6. An information display system according to claim 4, wherein three or more conductive strips extend along the shelf edge, and each display unit has a corresponding number of capacitor plates. 7. An information display system according to claim 4, claim 5 or claim 6, wherein a carrier intended to hold a strip of paper or the like so as to extend along the shelf edge, is used with electronic display units mounted on the shelf edge by means of a device comprising a ribbon of insulating material with a number of longitudinally extending conductive strips applied thereto and adapted to be received in or on the carrier. 8. An information display system according to claim 7, wherein the ribbon is received in or on the carrier either instead of, or in addition to, the paper labels. 9. An information display system according to claim 4, wherein an adhesive ribbon is applied to the shelf edge, the ribbon being formed with a number of longitudinally extending conductive strips. 10. An information display system according to claim 7, claim 8 or claim 9, wherein the conductive strips are formed on the ribbon by printing or otherwise applying an electrically conductive ink thereto. 11. A method of converting a conventional shelf edge display apparatus, wherein a carrier strip holds a number of tickets of flexible sheet material along a shelf edge so as to expose one face of the tickets, to accept electronic information display units, comprising applying to the carrier strip a ribbon of insulating material with a number of longitudinally extending conductive strips applied thereto, the ribbon being of a width similar to that of the tickets, and subsequently fixing a number of information display units to the carrier so that capacitor plates positioned on the information display units are positioned in close non-contact relation to respective conductive strips of the ribbon. 12. A method according to claim 11, wherein the carrier is formed of transparent material and overlies the tickets, and the ribbon is also transparent and is attached to the carrier in the area overlying the tickets. 13. An information display system for a store substantially as described herein with reference to Figure 1 or Figure 2 of the accompanying drawings. 14. A method of converting a conventional shelf edge information display system for a store substantially as described herein.

Inventors: SMITH MICHAEL WILLIAM, SMITH, MICHAEL, WILLIAM
Applicants: BSC DEVELOPMENTS LTD, SMITH MICHAEL WILLIAM, SMITH, MICHAEL, WILLIAM
Application year: 1994
Main classification: H04B5
IPC codes: G06F3, G08C17, H04B5